Rescue mode & OS reinstall

When to use rescue mode#

• The server does not boot after a kernel or GRUB update
• You lost the SSH key or locked yourself out with a firewall rule
• The file system needs fsck while unmounted

Boot into rescue#

Rescue mode boots a small Linux system from the network. Your disks are untouched and can be mounted:

avenlith server rescue enable web-01 --image rescue-2026
# after reboot, from the rescue system:
mount /dev/md0 /mnt
nano /mnt/root/.ssh/authorized_keys
avenlith server rescue disable web-01 && avenlith server reboot web-01

Reinstall the operating system#

avenlith server reinstall web-01 --image debian-13 --ssh-key default

Available images include Ubuntu 22.04/24.04/26.04, Debian 12/13, AlmaLinux 9/10, Rocky Linux 9, Windows Server 2022/2025 and Proxmox VE 9.